@Mail Groupware combines the ability to
share address books, calendar items, and
tasks among groups of users with optional
permission levels. It provides a complete Web-
based groupware system for users within
your organization and provides an Outlook
2003/2000 to Web synchronization utility for
Contacts and Calendar data.

ANts P2P realizes a third generation P2P net. It protects your privacy while you are connected and it makes you not trackable, hiding your identity (IP) and encrypting everything you are sending to/receiving from others.

AbiWord is a free word processing program similar to Microsoft Word. It is suitable for a wide variety of word processing tasks. It allows you to collaborate with multiple people on one document at the same time. It is tightly integrated with the AbiCollab.net Web service, which lets you store documents online, allows easy document sharing with your friends, and performs format conversions on the fly.

Active Calendar is a PHP class that generates calendars (month or year
view) as HTML tables (XHTML-Valid). It can produce static calendars
without any links or calendars with a week number column, navigation controls, a date picker
control, event days and content with event URLs, and linkable days (optionally URL
or Javascript). The layout can be configured using CSS, and JavaScript
is not required. The supported dates (on systems using a 32-bit signed
integer Unix time_t) are: 1902-2037 (Unix) and 1971-2037 (Windows), when
using the default PHP native date functions, and 100-3000 and later,
when using the ADOdb Date Library.

Aegisub is an advanced subtitle editor that assists in the creation of subtitles, translations, and complex overlays using audio or video. Developed by enthusiasts it builds on workflows created and perfected through professional, hobby, and everyday use.

AfterLogic WebMail Lite PHP is a Webmail script with a modern AJAX interface. It supports IMAP accounts, SMTP, and SSL (including Gmail). Users can check and send mail and use an address book. It provides a slick skin, a three-pane view, non-English language support, UTF-8 support, IMAP folders, and viewing and composing HTML mail. A MySQL backend is supported, with Web-based administration and installation and cPanel/Plesk/DirectAdmin integration.

Alexandria is a GNOME application to help manage a
book collection. It retrieves book information
(including cover pictures) from several online
libraries, allows you to search for a book (either
by EAN/ISBN, title, authors, or keyword), can
import and export data into ONIX, Tellico, and
EAN/ISBN-list formats, generates Web pages from
your libraries, allows marking your books as
loaned, saves data using the YAML format, features
an HIG-compliant user interface, shows books in
different views that can be filtered or sorted,
and handles book rating and notes.

Ampache is a Web-based audio file manager. It allows you to view, edit, and play your audio files via the Web. It has support for playlists, artist and album views, album art, random play, playback via HTTP with on-the-fly transcoding and downsampling, vote based playback, playback via MPD and Icecast, an integrated Flash player, and per-user themes and song play tracking. You can also link multiple Ampache servers together using XML-RPC. Ampache supports gettext translations and has full translations into many languages.